[gusmuh]

Could anyone help me find wiring diagrams for the heated seat switches for a 2003 and 2005 MDX or help me know how to rewire these?
History: I have a 2003 and replaced some of the wood grain trim with the trim from a 2005's trim I happened upon in a scrap yard. The center trim piece included the switches for the heated seats which connected to the existing wiring fine, but they must be wired differently, as the switch backlights and orange heater 'lo' lights don't work. The only lights on the switches that turn on are the orange 'hi' lights for both sides. I'm tying to rewire to have the switch backlights all work properly. I'm actually not really sure if the heaters themselves are working properly either.

Any help is appreciated. Thank you!

Extra info: I tested the 'lo' bulb in the place of the 'hi' bulb and it works, so I know it's not a burnt out bulb(s).
The 2005 switches are rotated 90 degrees from what the 2003 switches were.

Side note: I had to modify/customize the cabin light switch location since that was different.

 

[habbyguy]

Just different switches. You might be able to kludge it but the best option is to get the right switches (even if they "look sideways").

 

[habbyguy]

Thinking through this, I don't think the switches will fit in the same holes, so my advice is suspect (though still worth what you paid for it). ;-)

Here is the wiring diagram - I suspect (though don't guarantee) that you could swap the wires on the plug between the as-is, and to match the 2003 (the "main numbers" on the connector in the diagram) and the 2005 (the numbers in brackets - [3]). That should get it all working as it was designed that way.

If I'm reading this right, you'd move the wires like this:

Existing wiring plug number to Modified wiring plug number
1 (unchanged)
2 (unchanged)
3 to 4
4 to 6
5 to 3
6 to 5

That all presupposes how this works based on the switch diagram in the previous post. And I worked out that plan without looking at the numbers on the second diagram (which seem to say the same thing).

Easy peasy. ;-)

 

[gusmuh]

Wow! Thank you @habbyguy! This is beyond helpful!
I've never worked with switching wires in a harness like this, but you've laid it out so simply. It appears I can just swap where the wire ends enter the harness. Is that right? I don't know what the harness looks like inside and if the wires will be soldered inside there, or have some type of compression fitting. I plan to carefully open up the harness if I can, and investigate how I will mechanically get this done. If you have any pointers on this as I dig into it, please let me know.

I initially thought I would have to cut the wires, and add new sections of wire to reconnect the harness differently. Maybe that's still the process.

This is fantastic! I'll let you know how it goes.

 

[habbyguy]

Most of the plugs are designed around (IIRC) the Molex pins. They (male or female - can I still use those terms? LOL) have little "barbs" that hold them in place in the plastic housing. The right way to remove them is to have a special tool, which is essentially just a hollow tube just big enough to fit over the pin, but small enough to compress the barbs to allow pushing the pins out. You may be able to pry the barbs into submission one at a time with a VERY skinny screwdriver (like a jeweler's screwdriver) by flexing the cables one way (releasing the "lower barb") and then the other (releasing the "other barb". Or worst case, you COULD cut and splice (I'd recommend soldering and heat shrink tubing, just to be sure that the new connections are 100.000% reliable.

Make doubly certain to take photos of the "before state" of the plug so you can recreate the original wiring configuration if you happen to lose track of the process mid-stream. I suspect that the color coding on the schematic would be correct, but I never assume.

 

[habbyguy]

FWIW, here is the "official tool" I was talking about (just the first one I saw on Amazon, making no effort to find a better option - but at $7 delivered, it's worth having just to make the job simpler, and to reduce the chance of messing up a pin).

Here you can see what the tabs on the pin look like (the ones on the cylindrical portion of the pin, not the crimp areas at the rear, designed for capturing the wire)...

 

[gusmuh]

Awesome! Thank you for the tips and suggestions. I'll definitely be ordering one of those pin remover tools.

 

[gusmuh]

@habbyguy This is what the connectors look like. Will the Molex tool work on this? It almost looks like there are small blue release levers on this, and the pins don't look cylindrical like the molex ones.

 

[habbyguy]

Oops - the good news is that you can use a small flat tool (like a jeweler's screwdriver) to release the pins. Just pull lightly on a cable, and pry the tab on that connector down and it should wiggle right out of the connector. Sorry for the misinformation (something about the diagram made me think the pins were round - these are easier!).

 

[gusmuh]

No apology necessary! The most important part (rewiring order) is still applicable, and good news that it should be easier! Thank you!

 

[habbyguy]

Let us know how it comes out - there's always a pretty good chance someone else will be looking for this info sometime in the future, and I'm sure they'd love to see the outcome of this Frankenstein effort! ;-)

 

[gusmuh]

Alright, I did it, and learned things along the way. 🙂 I hope I did it right, as my first decision below may have caused the wiring to be out of order.

First off, I applied the diagram that shows the numbered locations to the bottom of the plastic harness where the wires enter the harness. Matching the view in the the picture below (pic shows wiring before changing the order) with the orientation of the black and white diagram that follows. I don't know if that was right, and it seems like it would change the wiring order if I looked at it from the top of the plastic harness.

The biggest challenge was figuring out how to get the wires out. It is impossible to remove the wires without first disconnecting the cover of the side of the harness my gently prying each side with a small flathead to un-attach that cover. After doing that, only then could I gently pry the tiny tabs using a flathead in the male side of the harness would the cable come out easily (at all). At first I got very frustrated and mangled the inside of the harness trying to pry the tiny tabs and tug the wires, and still couldn't get a wire out with a lot of hard pulling, etc. Only after I decided to try and open up the side cover was it possible and simple. 🙂 In the photos below, the first cover I took off broke off, but the second one I was more careful and it stayed attached. Even the one that broke off snapped right back in when I was done rewiring.

(below)Mangled harness while trying to figure out how to get the wires out before learning the side cover needed to come off (below)

Results: both the orange 'lo' and 'hi' lights light up now when pressed, where only the 'hi' worked before.
I haven't been able to do any more testing on the heating itself.
The white nighttime backlight in the middle of each switch isn't coming on, so I'll have to see if new bulbs fix that. The diagram seems to show that these lights would be dependent on the #1 and #2 wires - which aren't supposed to change...

Thank you for the help, and let me know if you have any other pointers - especially regarding my first step being correct or not - about assuming the diagram orientation that I did.

 

[habbyguy]

I agree that the #1 and #2 wires don't move, so chances are if the "full-time" lights aren't lit, there could be a problem with the lamps (or do they only come on with the headlights? I forget).

Otherwise, it sounds likely you've got it. I didn't know that the plug did have those "covers", which is kind of odd... but that's how Honda rolls, I guess. ;-)